Madan Jampani
Committed by Gerrit Code Review

[Emu] MutexExecutionService for running tasks that need to run only on a single instance.

Change-Id: Idf9fedbbf15c014e97c77db25aa608cd1db53b27
/*
* Copyright 2015 Open Networking Laboratory
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.onosproject.store.service;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.Executor;
/**
* Service for mutually exclusive job execution.
*/
public interface MutexExecutionService {
/**
* Runs the specified task in a mutually exclusive fashion.
* @param task task to run
* @param exclusionPath path on which different instances synchronize
* @param executor executor to use for running the task
* @return future that is completed when the task execution completes.
*/
CompletableFuture<Void> execute(MutexTask task, String exclusionPath, Executor executor);
}
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/*
* Copyright 2015 Open Networking Laboratory
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.onosproject.store.service;
/**
* The MutexTask interface should be implemented by any class whose
* instances distributed across controllers are intended to be executed
* in a mutually exclusive fashion.
*/
public interface MutexTask {
/**
* Begins the execution of a mutually exclusive task.
* The start method will be called once the "lock" is acquired.
* After the start method returns the lock is released and some other
* instance can take over execution.
*/
void start();
/**
* This method will be called when exclusivity of task execution
* can no longer be guaranteed. The implementation should take necessary steps
* to halt task execution in order to ensure correctness.
*/
void stop();
}